The invention relates to a device for measuring analog telephony signals, provided with
a converter, which can be linked to a subscriber line, for converting analog voltages present on the subscriber line into digital samples, PA1 a memory, linked to the converter, for storing a number of digital samples, PA1 a processor linked to the memory.
A device of this type is disclosed by EP 0 200 038 B1. The device; described herein measures analog voltages which are present on the line of a digital telephony system by converting these analog voltages, by means of the converter, into digital samples which are then stored in the memory. The processor checks, for each new sample, whether this is larger than the largest previously stored sample, in which case the largest previously stored sample is replaced by the new larger sample, or whether the new sample is smaller than the smallest previously stored sample, in which case, likewise, smallest the previously stored sample is replaced by the new smaller sample. Thus, after a certain time interval, a maximum and a minimum are found which form the actual maximum and minimum of all the samples taken during the particular time interval, and from which, based on a mathematical formula, new values are derived. A known device of this type has the drawback that it is designed in principle for locating faults, and that it is in principle unsuitable for real-time measuring of analog telephony traffic. It presents the problem that the determination of the actual maximum and minimum during the particular time interval is completely inadequate for analysing and interpreting very complex analog telephony traffic (involving ringing pulses, dialing pulses and billing pulses subject to considerable tolerances and, in general, pulses which look identical at first sight but may have a different previous and/or subsequent history).